12 RESOURCES OF TENNESSEE. 



Natural gas and oil conditions as applied to the Central 

 Basin. As above stated, the rocks of the Central Basin are 

 nearly all limestone. Limestone is formed by the chemical pre- 

 cipitation of lime carbonate from sea water, and by the shells 

 of animals that die in the sea. The large number of fossil 

 shells found in the limestones of the Central Basin prove that 

 they were formed at least in large ^art from animal remains. 

 The probability is that the amount of such remains was suffi- 

 cient to form a good supply of oil and gas. So we can reason- 

 ably conclude that the first condition for forming these prod- 

 ucts in commercial amount was supplied in the organic remains 

 put down with the rock. 



But when it comes to the other condition, that is the reser- 

 voir for containing the oil and gas, the prospect is not so favor- 

 able. It is true that the area itself is occupied by a great, flat 

 arch, upon the sides of which are numerous small, wave-like 

 folds. So far as this goes, the conditions are most favorable 

 indeed. But the rocks, like most limestones, are close textured. 

 There are no pores in which oil and gas may collect. The only 

 receptacles for such are in the joints that penetrate the lime- 

 stone beds. These, in places at least, are probably numerous 

 enough to form gas reservoirs of considerable importance, but 

 there is no fine-grained stratum to seal this in, and most of it 

 has escaped into the air. The nearest approach to a cover that 

 would retain the gas is in the Pierce shale, but this is a thin 

 formation, and is itself too limey and too much jointed for an 

 effective cover. 



As above stated, there are numerous localities over the Cen- 

 tral Basin where a small amount of gas and some oil have been 

 sealed in, and these are not infrequently struck in drilling for 

 water. But the oil is insignificant in amount where it occurs 

 at all, and the gas usually exhausts after a few days' flow. The 

 greatest supply of gas they could be expected to furnish would 

 be for private use, such as heating a residence, or a kitchen 

 range. In most cases, the supply would be too small to justify 

 the necessary piping even for one of these purposes. 



The question often comes up as to whether it would be advis- 

 able to go deeper in those wells of the Central Basin that pro- 

 duce gas. To this question, no general answer can be given. 



